December 2, 2022

expert reaction to UK Group A Strep outbreaks

We’ve had a few media requests from journalists about the recent deaths in children associated with Group A Streptococcus (GAS) infection, so here are some comments from scientists in case useful.

Dr Nathalie MacDermott, NIHR Academic Clinical Lecturer, King’s College London, said:

“Group A Streptococcus is a bacteria that can cause strep throat and scarlet fever, as well as skin infections. A small proportion of children with Group A Strep infection can develop an invasive infection where the bacteria enter the bloodstream and can cause sepsis or more deep seated infections such as chest infections, bone and joint infections or abscesses. These children can become very unwell very quickly, so it is important for parents to watch out for signs that their child is becoming increasingly unwell such as a persistently high temperature that won’t come down with normal measures, being irritable or difficult to wake, difficulty breathing, a rash that doesn’t fade when pressed on and is spreading, red and swollen joints or refusing to walk or use an arm. 

“Prompt treatment with antibiotics can manage these infections, but it is important they are recognised and treated quickly. Prompt treatment of Scarlet Fever and Strep throat also reduce the chances of a child developing invasive Group A Strep and reduce the chances of the infection spreading to other children at school or household members.”

Dr Elizabeth Whittaker, Honorary Clinical Senior Lecturer, Imperial College London, said:

“Group A strep infections are very common in children, and thankfully, severe cases (known as invasive group A strep, causing sepsis, meningitis, pneumonia) are rare.

“During the first two years of the pandemic, we saw very little group A Strep and it has started to circulate again in 2022 as restrictions have been lifted.  Usually we see a high number of cases in late spring or early summer, often after chicken pox infections.  High numbers at this time of year are unusual and probably occurring as normal seasonality has not yet returned.  Tragically, when there are high numbers of infections, the severe cases will also occur. We are seeing more pneumonia than usual, most likely as group A strep infections are coinciding with the peak in winter respiratory viruses which are typical for this time of year.

“Severe invasive group A Strep is rare, and parents don’t need to worry, but do need to be aware when and how to seek medical attention. We would normally expect fevers due to viral infections to settle within 4/5 days, so if they are persisting, or are associated with lethargy, difficultly breathing, poor drinking or wet nappies/urine output, families should get in touch with NHS111 for advice.”

Prof Adam Finn, Professor of Paediatrics, University of Bristol, said:

“Group A streptococcus, also called Streptococcus pyogenes and sometimes abbreviated to GAS is a common bacterium found in the mouth and throat in children and less commonly in adults. It can cause a range of problems – most commonly sore throats (“strep throat”) or pharyngitis but also “scarlet fever” in which the child develops a bright red generalised rash. If the bacterium gets under the skin or otherwise into the blood or other normally sterile tissues it can spread rapidly causing cellulitis and in severe cases abscesses in different places, necrotising fasciitis or sepsis with involvement of multiple organs. Some strains release powerful toxins which can cause toxic shock syndrome. GAS also causes a range of serious post-infectious syndromes including rheumatic fever which can affect the brain, the heart and the joints and glomerulonephritis, an inflammatory condition of the kidneys. So, this is a bug that can cause a wide range of problems.

“Fortunately, it is reliably sensitive to penicillin, so if infections are diagnosed early they can usually be effectively treated. However, this can be difficult in invasive disease as it can progress very rapidly.

“Lots of infections became rarer during the restrictions of the recent pandemic and are now coming back rapidly as mixing normalises. GAS is no exception and we have been seeing increasing numbers of cases in recent months.

“GAS rarely causes meningitis and for this reason is less well-known than other infections that do because meningitis is a particular disease of concern to parents. However, it causes as much serious disease as other meningitis-causing bacteria. For this reason we badly need to progress work on developing a vaccine to prevent GAS infection.”

Prof Shiranee Sriskandan, Professor of Infectious Diseases, Imperial College London, said:

What’s causing these recent outbreaks from Strep A?

“The outbreaks are caused by strains of Strep A that are good at causing throat infections including tonsillitis and also scarlet fever. This type of infection spreads readily among younger children under 8.

“There are outbreaks of scarlet fever in primary school aged children in different parts of the country- this is not in itself unusual but the timing and number of outbreaks at present  is unusual. Outbreaks of scarlet fever (which is a very visible sign of Strep A infection) are a marker of how much Strep A is circulating in the community. And any increase in the reservoir of community infection will unfortunately lead to an increase in the very rare instances of invasive infection that we see, in both children and adults.”

Are these outbreaks linked?

“There will often be some links between outbreaks of scarlet fever between different schools- that would not be surprising since children do mix with children from different schools. We also know that the strains of Strep A (Streptococcus pyogenes) that cause the more common conditions like tonsillitis are the same strains that are capable of causing the much rarer invasive infections.

“i.e. The more serious infections are caused by strains that are more or less identical to strains causing scarlet fever or tonsillitis.”

Can we expect to see further outbreaks in the following days?

“While the rates of scarlet fever are high and are linked to outbreaks, unfortunately we may see further cases of invasive infection but it’s important to realise that these invasive infections, especially in children, are very rare.

“We normally see an increase in scarlet fever and scarlet fever outbreaks in March and April, which declines naturally, helped by school holidays. This year is certainly unusual. But the onset of holidays may provide an interruption in transmission.”

Are these deaths from Strep A rare?

“Deaths from Strep A are rare, but that is mainly because invasive Strep A infections are thankfully very infrequent.

“Children have a lower mortality than adults from invasive Strep A; deaths in children are not expected.

“Strep A is however an important cause of unexpected death from ‘sepsis’ in children, and reports in the media sometimes do not explain this.

“One thing to be aware of, is that Strep A, in the invasive setting, has the capacity to make people very sick very quickly, which is a major challenge for clinicians. So people can deteriorate very quickly. 

“It is particularly hard when treating children, who may not be able to convey what symptoms they have.”  

Could these outbreaks/deaths be linked to lower immunity post-covid, etc?

“Potentially. Children normally catch scarlet fever in their first year at school, if at all. We know that scarlet fever rates plummeted during 2020-2021. We therefore think that school aged children may not have built up immunity to Strep A, and so we now have a much larger cohort of non immune children where Strep A can circulate and cause infection. This is coupled with an unexpected rise in Strep A infections at the wrong time of the year, when winter viruses like RSV are circulating.”

“Parents and carers should be alert to the symptoms of scarlet fever which include a high fever, sore throat or tonsillitis, with a prickly rash  (that will be red on light coloured skins) and often a bright red tongue that can look like a strawberry. Scarlet fever just like strep A tonsillitis is very infectious but responds quickly to antibiotics. Children should not go back to school or nursery until they are at least 24 hours into taking the antibiotics. Scarlet fever is described here https://www.nhs.uk/conditions/scarlet-fever/. If your child has evidence of a strep A infection, you should seek medical advice via your GP or 111.

“The signs and symptoms of the rarer more serious invasive infections in children can include an ongoing fever, lethargy,  pain in the muscles , increasing redness of the skin, vomiting, and dry nappies or reduced urine production. Depending on which part of the body is affected, children may have a worsening cough or fast breathing or difficult breathing. Medical advice should be sought without delay . It is important to explain if they have been in contact with other cases of Strep A or scarlet fever.”

Dr Chrissie Jones, Associate Professor of Paediatric Infectious Diseases at the University of Southampton, and Southampton Children’s Hospital, said:

“Group A Strep is a common bacteria that normally causes mild illness and we see increases in cases every few years. However, at the moment, we are a seeing a higher than usual number of cases of Group A Strep infections and a very small number of these children have had a serious illness. Social mixing and and a higher amount of bacteria circulating in the community is the most likely reason for the increase in cases of severe illness. It is not currently thought that there are new or different strains of Group A Strep which are causing this rise in cases.

“Group A strep is found can found in the back of the throat or on the skin. In most people, it usually only causes a mild infection. So, a child might be generally well but have a sore throat or minor skin infection or an illness called called scarlet fever, where children have a fever, a sand-paper-like rash, and a sore throat.  In a small number of children, Group A strep can cause more severe throat or chest infections, or sepsis.

“There are also all the normal seasonal viruses going around at the moment, so many children will have a sore throat or fever won’t have a bacterial infection caused by Group A strep. These infections will normally resolve without treatment, but if they are not getting better then it is important to seek medical review.

“Things parents can look out for include: a high fever that is not settling, severe muscle aches, pain in one area of the body, a spreading redness on the skin, is breathless or having trouble breathing, excessive sleepiness or irritability, they should be reviewed by a medical professional.

“Group A strep infections are well treated with antibiotics and this reduces the chance of complications and reduces spread to other people. Most children will be treated safely with oral antibiotics at home, but some children will need to be seen in hospital and treated with antibiotics through the vein.”

Prof Paul Hunter, Professor in Medicine, University of East Anglia (UEA), said:

“Group A streptococci (Streptococcus pyogenes) (GAS) are a relatively common infection that is often asymptomatic and when symptomatic most typically causes a sore throat though at times can cause other more serious diseases such as scarlet fever, skin infections, rheumatic fever and rarely streptococcal toxic shock syndrome. As we have seen here it can also cause death albeit rarely.

“The infection is spread from one person to another typically through respiratory droplets but also by contact with secretions, such as saliva, wound discharge, or nasal secretions.

“Group A streps remain sensitive to penicillin and early treatment will substantially reduce the risk of severe disease. But most sore throats are viral and penicillin can do more harm than good when it is not needed. With a strep sore throat the child tends to have a higher temperature and swollen lymph glands but it is not always easy to distinguish a strep sore throat from the more common viral sore throat. There are some rapid tests from group A streps that could be used in the surgery but I am not sure how widely available they are.

“In protracted or extensive outbreaks in particular settings such as a school, military camp, prison, or nursing home then treatment by penicillin may be given to all people in that institution. But more general treatment in the community is rarely if ever justified.

“The critical thing is if your child has a sore throat, particularly if are unwell in themselves and have a high fever then either contact your GP or NHS 111.”

Dr Michael Head, Senior Research Fellow in Global Health, University of Southampton, said:

“From the UK public health surveillance, there are increased numbers of cases of scarlet fever, and also invasive group A streptococcal infection, that would normally be seen at this time of year.

“However, reporting across the season is lower than the equivalent 5 year average, and during 2017/18, cases across the year were at much higher levels than are being observed this year.

“After the pandemic response over the last 2 and a half years, it might be that we’re not yet back in line with usual seasonal expectations, and we do usually observe natural fluctuations in disease patterns.”

Prof Beate Kampmann, Professor of Paediatric Infection & Immunity and Director of The Vaccine Centre, London School of Hygiene & Tropical Medicine, said:

“Group A strep is a well known bacterium that usually causes fever and throat infections and sometimes a condition called scarlet fever. These tend to be fairly harmless.

“In very rare circumstances when the bacterium produces a toxin  it can gain access to the bloodstream and cause really serious illness such as heart inflammation, necrotising fasciitis, sepsis and  toxic shock with organ failure, and this unfortunately appears to have been the case of the tragic deaths of the schoolchildren.

“There is no vaccine-yet- but it usually responds well to simple antibiotics like Penicillin- except if a shock-like picture needs intensive care and all the support that comes with it.

“It is a very rare condition, but due to the effects of the toxin primarily it can evolve into a serious picture, and if parents are concerned about their child looking very ill with symptoms of fever, vomiting, muscle aches, rash they should always promptly seek medical advice.”

Dr Simon Clarke, microbiologist at the University of Reading, said:

“Group A Streptococcus is a spherical bacteria, roughly 1 thousandth of a millimetre in diameter.  It’s fairly common and lives primarily in the throat and is carried around by some people without ever causing them any problems.  But sometimes it causes disease which can range from mild cases of sore throat to more serious illnesses like scarlet fever and in rare incidences necrotising fasciitis, otherwise known as “flesh eating disease”.

“It’s important to remember that infections like this never occur at a constant rate, you get peaks and troughs in numbers and from that we work out an average.  There is a suggestion that there have been more cases lately than we would expect, but that might be a statistical blip; publication of diagnosed infection numbers is slow and infrequent compared to the sort of data that was released during the pandemic.  Similarly, I’ve seen no data to indicate that a new strain is responsible for the current cases.  It’s also important to stress that this infection, when diagnosed quickly, can easily be treated with antibiotics, and only in extreme cases does it need hospitalisation.    I’m unaware of any factor linking these reported deaths, so it’s impossible to link them, but I do expect there to be further cases over the coming weeks and months.

“It strikes me that as we are seeing with flu at the moment, lack of mixing in kids may have caused a drop in population wide immunity that could increase transmission, particularly in school age children.”

Declared interests

Dr Simon Clarke: “No conflicts of interest to declare relevant to this.”

Prof Adam Finn: “No relevant conflicts.”

For all other experts, no reply to our request for DOIs was received.